Mission????

A lot of my friends are starting their mission papers or have their calls. I'm excited for them, but I feel a little left out. I am starting to think about a mission, but I am right in the middle of the nursing program and to be honest I'm scared of going on one:) There is a part of me that wants to go, and another part that really doesn't think I could do it....and I don't want to go in the middle of school. Is that bad? Is it selfish? I need some advice people!